Optical radar system transmitters may have need for a transmitter antenna pattern which is shell-like so that the effective field-of-view is within a very small .DELTA..theta. range offset in the range of from zero to 90 degrees from a central axis. In such systems it is desirable for the nominal angle of the shell-like pattern off the central axis to be a constant. However, no such systems are known to be in the prior art.
Applicant has, however, become aware of a shell-like optical pattern system which was developed concurrently with the instant invention. It differs from applicant's invention in that a cross section of the pattern of the concurrent art is rectangular in shape. This configuration complicates range determinations since the off-axis angle changes with the target direction.